Humans ; Cardiomyopathy, Hypertrophic/genetics* ; Mutation ; Phenotype ; Ryanodine Receptor Calcium Release Channel/genetics* ; Tachycardia, Ventricular/genetics*

Humans ; Cardiomyopathy, Hypertrophic/genetics* ; Mutation ; Phenotype ; Ryanodine Receptor Calcium Release Channel/genetics* ; Tachycardia, Ventricular/genetics*

Electrocardiography ; Humans ; Mutation ; Phosphorylation ; Ryanodine Receptor Calcium Release Channel/genetics* ; Tachycardia, Ventricular/genetics*

OBJECTIVE: To explore the clinical and genetic characteristics of five children with Catecholaminergic polymorphic ventricular tachycardia (CPVT). METHODS: Five children with clinical manifestations consistent with CPVT admitted to the Department of Cardiology of Children's Hospital Affiliated to Zhengzhou University from November 2019 to November 2021 were selected as the study subjects. Their clinical data were collected. Potential variants were detected by whole exome sequencing, and Sanger sequencing was used to verify the candidate variants. All patients were treated with β-blocker propranolol and followed up. RESULTS: All patients had developed the disease during exercise and presented with syncope as the initial clinical manifestation. Electrocardiogram showed sinus bradycardia. The first onset age of the 5 patients were (10.4 ± 2.19) years, and the time of delayed diagnosis was (1.6 ± 2.19) years. All of the children were found to harbor de novo heterozygous missense variants of the RYR2 gene, including c.6916G>A (p.V2306I), c.527G>C (p.R176P), c.12271G>A (p.A4091T), c.506G>T (p.R169L) and c.6817G>A (p.G2273R). Among these, c.527G>C (p.R176P) and c.6817G>A (p.G2273R) were unreported previously. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the c.527G>C (p.R176P) was classified as a pathogenic variant (PS2+PM1+PM2_Supporting+PM5+PP3+PP4), and the c.6817G>A (p.G2273R) was classified as a likely pathogenic variant (PS2+PM2_Supporting+PP3+PP4). The symptoms of all children were significantly improved with the propranolol treatment, and none has developed syncope during the follow up. CONCLUSION Discovery of the c.527G>C (p.R176P) and c.6817G>A (p.G2273R) variants has expanded the mutational spectrum of the RYR2 gene. Genetic testing of CPVT patients can clarify the cause of the disease and provide a reference for their genetic counseling.
Child ; Humans ; Mutation ; Propranolol ; Ryanodine Receptor Calcium Release Channel/genetics* ; Syncope ; Tachycardia, Ventricular/diagnosis* ; United States

AIMTo detect the expression of ryanodine receptor (RyR) subtypes in normol rat airway smooth muscle cells(ASMCs) and changes during chronic asthma formation.

METHODSASMCs were cultured with collagen enzyme digestion method. The expression of subtypes of RyR were detected by RT-PCR. Purified PCR product linked with pGEM-T vector to make DNA sequence assay. Chronic asthma model was made with OVA, the changes of RyRs detected by RT-PCR.

RESULTSAll subtypes of RyR were expressed in airway smooth muscle cells of normol rat. The expression of RyR1 increased obviously compared with control group (P < 0.05) on chronic asthma.

CONCLUSIONCo-expression of three subtypes of RyR in ASMCs of normal rat, indicate that there are complicated intercellular Ca2+ regulation mechanism in ASM, moreover RyR1 might play a role during asthma development.

Animals ; Asthma ; metabolism ; Bronchi ; Male ; Myocytes, Smooth Muscle ; metabolism ; Protein Isoforms ; genetics ; metabolism ; RNA, Messenger ; genetics ; Rats ; Rats, Wistar ; Ryanodine Receptor Calcium Release Channel ; genetics ; metabolism

Adolescent ; Death, Sudden, Cardiac ; etiology ; Female ; Humans ; Ion Channels ; physiology ; Mutation ; Ryanodine Receptor Calcium Release Channel ; genetics ; Syncope ; etiology ; Tachycardia, Ventricular ; genetics

OBJECTIVETo investigate changes in adenosine triphosphatase (ATPase) activity and expression of ryanodine receptor 1 (RyR1) mRNA in formation of pressure ulcer at early stage, and to analyze its mechanism.

METHODSThirty-six male Sprague-Dawley rats were divided into three groups according to the random number table as follows, with 12 rats in each group. (1) Ischemia-reperfusion (IR) for 3 times (3IR) group: unilateral gracilis of rats were loaded with 22.47 kPa pressure with a special pressure apparatus for 2.0 h to simulate ischemia, and unloaded for 0.5 h to simulate reperfusion. All rats were treated with above-mentioned manoeuvre for 3 times. (2) IR for 5 times (5IR) group: rats were treated with the same manoeuvre as that in 3IR group except for IR for 5 times. (3) CONTROL GROUP: gracilis of rats were subjected to a load of 0 kPa pressure. Rats in 3IR, 5IR groups were sacrificed, and then central part of pressured tissue was harvested for detection of activity of total ATPase, Ca(2+)-Mg(2+)-ATPase, and Na(+)-K(+)-ATPase with spectrophotometer colorimetry, the level of malondialdehyde (MDA) with enzyme linked immunosorbent assay (ELISA), and the level of RyR1 mRNA with real-time fluorescence quantitative RT-PCR. The same part of gracilis muscle of rats in control group was harvested for determination of indexes as above. Data were processed with one-way analysis of variance. Pearson correlation analysis was respectively performed between total ATPase activity and MDA level, total ATPase activity and RyR1 mRNA expression level, and RyR1 mRNA expression level and MDA level.

RESULTSActivity of total ATPase, Ca(2+)-Mg(2+)-ATPase, Na(+)-K(+)-ATPase in control group was respectively (1.629 ± 0.004), (0.907 ± 0.061), (0.697 ± 0.083) U/mg, all significantly higher than those in 3IR group [(1.365 ± 0.004), (0.784 ± 0.020), (0.581 ± 0.017) U/mg, with F value respectively 1707.0, 29.8, 15.2, P < 0.05 or P < 0.01] and 5IR group [(1.055 ± 0.049), (0.619 ± 0.016), (0.436 ± 0.039) U/mg, with F value respectively 1107.0, 169.9, 65.7, P values all below 0.01], and the values of 3 indexes in 5IR group were obviously lower than those in 3IR group (with F value respectively 322.8, 341.7, 94.0, P values all below 0.01). The level of MDA in control group [(7.5 ± 0.6) nmol/L] was lower than that in 3IR group [(9.9 ± 0.6) nmol/L, F = 53.2, P < 0.01] and 5IR group [(13.7 ± 1.3) nmol/L, F = 76.9, P < 0.01]. There was also statistical difference in MDA level between 3IR group and 5IR group (F = 82.9, P < 0.01). Expression level of RyR1 mRNA in control group (8.5 ± 4.2), which was similar to that in 3IR group (3.3 ± 2.1, F = 0.9, P > 0.05), was significantly higher than that in 5IR group (0.6 ± 0.5, F = 23.6, P < 0.05); while the RyR1 mRNA expression level was lower in 5IR group than in 3IR group (F = 39.3,P < 0.05). Activity of total ATPase was negatively correlated with MDA level (r = -0.918, P < 0.01). Activity of total ATPase was positively correlated with RyR1 mRNA expression level (r = 0.713, P < 0.01). RyR1 mRNA expression level was negatively correlated with MDA level (r = -0.702, P < 0.01).

CONCLUSIONSEnergy dysbolism may be an initial factor in the development of pressure ulcer at early stage. Calcium overload injury in pressure tissue can be identified by determination of RyR1 mRNA expression.

Adenosine Triphosphatases ; metabolism ; Animals ; Male ; Muscle, Skeletal ; metabolism ; Pressure Ulcer ; metabolism ; RNA, Messenger ; genetics ; Rats ; Rats, Sprague-Dawley ; Ryanodine Receptor Calcium Release Channel ; genetics ; metabolism

PURPOSE: The underlying cause of myasthenia gravis (MG) is unknown, although it likely involves a genetic component. However, no common genetic variants have been unequivocally linked to autoimmune MG. We sought to identify the genetic variants associated with an increased or decreased risk of developing MG in samples from a Korean Multicenter MG Cohort. MATERIALS AND METHODS: To determine new genetic targets related to autoimmune MG, a whole genome-based single nucleotide polymorphisms (SNP) analysis was conducted using an Axiom(TM) Genome-Wide ASI 1 Array, comprising 598375 SNPs and samples from 109 MG patients and 150 neurologically normal controls. RESULTS: In total, 641 SNPs from five case-control associations showed p-values of less than 10(-5). From regional analysis, we selected seven candidate genes (RYR3, CACNA1S, SLAMF1, SOX5, FHOD3, GABRB1, and SACS) for further analysis. CONCLUSION: The present study suggests that a few genetic polymorphisms, such as in RYR3, CACNA1S, and SLAMF1, might be related to autoimmune MG. Our findings also encourage further studies, particularly confirmatory studies with larger samples, to validate and analyze the association between these SNPs and autoimmune MG.
Antigens, CD/genetics ; Asian Continental Ancestry Group/genetics ; Calcium Channels/genetics ; Female ; Genetic Predisposition to Disease/genetics ; Genotype ; Humans ; Male ; Myasthenia Gravis/*etiology ; Polymorphism, Single Nucleotide/genetics ; Receptors, Cell Surface/genetics ; Ryanodine Receptor Calcium Release Channel/genetics

OBJECTIVETo investigate the effects of losartan on mRNA expression of myocardial sarcoplasmic reticulum calcium handling proteins (SERCA2, RyR2 and PLB) and the role of which in prevention of chronic heart failure in rabbit.

METHODSAfter chronic heart failure was induced by ligation of the left anterior descending artery in rabbits, the animals were treated with losartan. At 8 weeks after ligation, left ventricular function, hemodynamic parameters, and SERCA2, RyR2, PLB mRNA expressions were observed.

RESULTSCompared with the control group (group C), LVEDP in the infarcted group (group I) increased (P < 0.01), while +dp/dt(max) and -dp/dt(max) decreased significantly (P < 0.01). LVEDP was lower but +dp/dt(max) and -dp/dt(max) significantly higher in the losartan treated group (group L) than those in group I (P < 0.05). SERCA2, RyR2, and PLB mRNA expressions in group I were remarkably lower than those in group L (P < 0.01) and group C (P < 0.01), respectively.

CONCLUSIONLosartan can improve cardiac function, probably owing to its upregulating mRNA expressions of myocardial sarcoplasmic reticulum Ca(2+) handling proteins (RyR2, SERCA2 and PLB) in the prevention of heart failure.

Angiotensin II Type 1 Receptor Blockers ; pharmacology ; Animals ; Calcium ; metabolism ; Calcium Channels ; drug effects ; Calmodulin ; biosynthesis ; genetics ; Female ; Heart Failure ; drug therapy ; metabolism ; Losartan ; pharmacology ; Male ; Rabbits ; Ryanodine Receptor Calcium Release Channel ; biosynthesis ; Sarcoplasmic Reticulum ; drug effects ; metabolism

The mRNA and protein expression of skeletal dihydropyridine receptor isoform alpha1 subunit (DHPR(alpha1)) and ryanodine receptor(1-3) (RyR(1-3)) during chronic electrical stimulation (CES) of phrenic nerve have rarely been explored. In the present study, we explored the signal translation mode of calcium release unit in diaphragm muscle of rabbits after CES. Thirty rabbits were used and randomly divided into the normal, 10, 20, 50 and 100 Hz groups. Phrenic nerve was continuously (5 weeks, 2x 2 h/d) stimulated at 10, 20, 50 and 100 Hz respectively (impulse width 0.2 ms, 3~6 waves/time, 45 times/min, 10~20 V). Reverse transcription PCR and immunohistochemical methods were employed. The results showed that mRNA and protein expressions of DHPR(alpha1) and RyR(1) in 10 and 20 Hz groups were more significantly lower than those in the control group (P<0.01), but mRNA and protein expressions of DHPR(alpha1) and RyR(1) were significantly higher in 50 and 100 Hz groups than those in the control group (P<0.01); a lower level of mRNA expression of RyR(2) was found in 10 and 20 Hz groups. It is suggested that the calcium release unit and the signal transduction mode between DHPR and RyRs were altered from conformational changes of linked proteins to Ca(2+)-induced Ca(2+) release (CICR) in the diaphragmatic muscle of rabbits after chronic low-frequency electrical stimulation of phrenic nerve for 5 weeks.
Animals ; Calcium ; metabolism ; Calcium Channels, L-Type ; biosynthesis ; genetics ; Diaphragm ; metabolism ; physiology ; Electric Stimulation ; Female ; Male ; Muscle, Skeletal ; metabolism ; physiology ; Phrenic Nerve ; metabolism ; physiology ; RNA, Messenger ; biosynthesis ; genetics ; Rabbits ; Random Allocation ; Ryanodine Receptor Calcium Release Channel ; biosynthesis ; genetics